Sea Surface Temperature and ENSO Outlook
for April - September 2019
(Issued: 25 Mar, 2019)
Positive SST anomalies are likely to remain across most of the tropical Pacific Ocean for April – June 2019, and strengthen for July – September 2019. Four out of five dynamical coupled models predict a Niño3.4 index exceeding +1oC to persist through April – June 2019 and slightly increase through July – September 2019. Positive SST anomalies are predicted over the Indian Ocean basin without any significant zonal gradient for April – June 2019. Positive SST anomalies over the western Indian Ocean are expected to be enhanced for July – September 2019, which correspond to the weak positive phase of the Indian Ocean Dipole index. In summary, based on the running 3-month mean Niño3.4 index, the APCC ENSO outlook suggests moderate El Niño conditions (~55% probability) for April – June 2019 and the conditions are likely to strengthen to moderate to strong levels for July – September 2019.
Fig. 1. Predicted Niño 3.4 Index from individual models (A, B, C, D, and E) and the Multi-Model Ensemble (MME).
Fig. 2. Predicted Indian Ocean Dipole mode index (IODMI) from individual models (A, B, C, D, and E) and the MME.
Fig. 3. Multi-model ensemble (MME) forecasts of SST anomalies for April - June 2019 (top) and July - September 2019 (bottom). Anomalies are computed with respect to the common base period of participating models in the APCC MME prediction (1983-2010).
Fig. 4. Probabilistic MME forecasts of the status and intensity based on 3-month mean Niño3.4 index for four overlapping 3-month mean periods. Anomalies are computed with respect to the common base period of participating models in the APCC MME prediction (1983-2010).